In recent years there has been great effort expended by researchers in a medical field for developing an intravenous feeding pump adapted to accurately measure and positively pump parenteral solutions from a supply container into the veins of a patient without having to rely upon the force of gravity alone. Such pumps have many advantages in administering the parenteral fluid and many designs have been suggested, including two covered by patent applications of this applicant, namely, Ser. No. 431,753, filed Jan. 8, 1974 now U.S. Pat. No. 3,874,826, and Serial No. 488,580, filed July 15, 1974.
Doctors often desire to introduce drugs into the blood stream of a patient, and whenever the patient is being fed intravenously, it is usually desirable to introduce the drug through the intravenous feeding system, as by injecting into the delivery tube to the patient. Quite often the drug is of such a character that it is advisable to dilute the drug in some predetermined ratio with the volume of solution being fed to the patient. The present device is directed to that end and provides a means whereby a desired volume of drug can first be diluted in a variable volume of the parenteral solution and then fed to the patient if that is desired. Then, as soon as the drug has been administered, it is usually desirable to return to the feeding of the parenteral solution. The necessary changes of course must be done with a minimum of contamination of the drug or the solution from contact with the air during the various steps of the process, and great care must be taken to prevent the feeding of air into the blood stream of the patient.
The device of the present invention is adapted to enable a hospital staff to use premeasured doses of a prescribed medication (prepared either by a drug manufacturer or by a hospital pharmacy in advance); to encapsulate the dosage into a suitable capsule which can readily be inserted into the intravenous feeding system with a minimum chance for contamination; and then to return to the feed of the parenteral solution without breaking the connection between the supply container of parenteral fluid and the needle which is inserted into the blood vessel of the patient. It is particularly adapted to be used in cooperation with an intravenous feeding pump, such as the ones suggested by the applicant's aforementioned patent applications, or any of the other intravenous feeding pumps which have been designed for this purpose.